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Monday, 23 February 2015

I've been to see my chums at LAM Communications today and I brought home one of these:

It's a Yaesu SCU-17 radio interface unit. I've owned a lot of radios in my time, the most "modern" perhaps being the Kenwood TS-990 and the Yeasu FT-3000. Both these radios have USB ports on the rear and built in sound cards. You connect the USB port to a PC and low and indeed behold, you have an audio device to send Audio to and receive Audio from the Radio, you also have a "Virtual" COM port that you can use for CAT control. The other really neat feature of the FT-DX3000 that I believe is unique to that radio, is that you also get a second "virtual" COM port that you can use to control PTT, FSK & CW switching from PC applications. The 990 doesn't have this second virtual port and hence you still need a simple interface between the radio and the PC if you want to hard control the PTT line, run FSK RTTY or use an external CW keyboard.

This interface from Yaesu kind of gives you a half way house. I have two "virtual" COM ports, one for CAT control and the second for PTT & FSK - but unfortunately no CW keying so I've had to construct another simple interface to do that on the new FT-DX5000 I have:

It seems a real shame to me that I need to build an external one transistor switch to use a CW keyboard with a very expensive radio! If anyone knows different to me then please let me know. The 990 I have has two of those circuits (actually opto isolated equivalents) for CW and FSK keying.

Th Yaesu SCU-17 also connects to the Packet and RTTY rear connectors on the 5000 and takes care of AFSK audio interfacing as well as the FSK switching and CAT control.

I had some difficulty getting the COM ports to be recognised by the Logger32 software that I use here; I ended up swapping some ports about and assigning the SCU-17 ports a number under 10. Once I had done that all seemed to be well.

There is, however, this additional board installed either side of L308<<something>> where the something is obscured by the cables. You can see the board in the photo above - it's got G086C written on it. Any ideas what this is? This is the RF connections from the board:

There also seems to be a cable disconnected to the front panel:

Also I can see what looks like a voltage regulator in the middle of this photo here:

The power out is also lower than I would expect on 4M, perhaps the PA hasn't been modified correctly: